1. Field of the Invention
The present invention relates to an interconnection agreement determining system, apparatus, and method that, in short message service originating and terminated control in mobile communication networks, make determination as to whether carriers have a short message service interconnection agreement with each other and that are compatible with number portability.
2. Description of the Related Art
The Short Message Service (SMS) has been provided as a communication service in mobile communication networks. The short message service is a message exchange service through which communication terminals can exchange text data having a limited length.
If an originating terminal which wants to send a short message and a receiving terminal to which the short message is directed subscribe to different carriers, they cannot send or receive the short message unless the carries have a short message service interconnection agreement (hereinafter referred to as an “SMS interconnection agreement”) with each other.
Therefore, a mobile switching center in the location area that has received a request for transferring a short message from an originating terminal must determine whether the carrier to which the originating terminal subscribes and the carrier to which the receiving terminal subscribes have an SMS interconnection agreement with each other. The mobile switching center performs control operations such as transferring the short message received to a Short Message Service Center (SMSC) only if the mobile switching center determines that the carriers have such an agreement with each other.
FIG. 4 shows a conventional SMS originating and terminated control procedure. The SMS originating and terminated control procedure includes two procedures: an SMS originating (Short-Message-Mobile-Originating: SM-MO) control procedure for sending a message from an originating terminal to a short message center and an SMS terminated (Short-Message-Mobile-Terminated: SM-MT) control procedure for receiving, by a receiving terminal, a short message sent from a short message service center (hereinafter referred to as a “SMSC”). Referring to FIG. 4, a method in the SMS originating and terminated control procedure for determining whether carriers have an SMS interconnection agreement with each other will be described.
When an originator enters text data to be sent as a short message and the telephone number of the receiving communication terminal 10 by operating an originating communication terminal 10 in the SMS originating control procedure, the originating communication terminal 10 generates and sends a short-message-mobile-originating (SM-MO) signal containing the entered text data and the telephone number of the receiving communication terminal 10 (Process P101).
The short-message-mobile-originating signal is sent to a (location-area) mobile switching center 200 that services the area in which the originating communication terminal 10 is currently located and that is operated and managed by the carrier to which the originating communication terminal 10 subscribes (hereinafter referred to as the “location-area MSC”). When receiving the short-message-mobile-originating signal, the location-area MSC 200 determines whether the carriers have an SMS interconnection agreement with each other (Process P102).
At this time, the location-area MSC 200 identifies the subscription carrier of a receiving communication terminal 10 from the telephone number of the receiving communication terminal 10 contained in the short-message-mobile-originating signal it has received to determine whether the carriers have an SMS interconnection agreement with each other. In particular, the location-area MSC 200 obtains the receiving communication terminal's 10 telephone number contained in the short-message-mobile-originating signal; the telephone number is a number in a system called the MSISDN (Mobile Station International Integrated Service Digital Network Number). An MSISDN contains a Country Code (CC) identifying a country and a Network Destination Code (NDC) identifying a carrier. The location-area MSC 200 determines from the CC and NDC in the MSISDN the carrier to which the receiving communication terminal 10 subscribes. The location-area MSC 200 then determines whether the carrier to which the receiving communication terminal 10 subscribes has an interconnection agreement with the carrier of the network on which the location-area MSC locates, from information in the SMS interconnection agreement participating carriers held by the location-area MSC 200.
If the location-area MSC 200 determines that the carriers have SMS interconnection agreement with each other, the location-area MSC 200 transfers the short-message-mobile-originating signal to the SMSC 40 (Process P103); otherwise, it does not transfer the short-message-mobile-originating signal.
When the SMSC 40 receives the short-message-mobile-originating signal, the SMSC 40 returns an SM-MO acknowledgement to the location-area MS C200 (Process P104), which in turn transfers the SM-MO acknowledgement to the originating communication terminal 10 (Process P105). Then, the SMS originating control procedure ends.
When receiving the SM-MO signal, the SMSC 40 performs the SMS terminated control procedure. In particular, the SMSC 40 transfers a short-message-mobile-terminated (SM-MT) signal to an MSC that is a gateway to another network (hereinafter referred to as a “gateway MSC”) 500 (Process P106). When receiving the SM-MT signal, the gateway MSC 500 sends an SRIForSM (Send Routing Information for SM) signal (routing interrogation signal) to a Home Location Register (HLR) 30, which is a device that maintains subscriber information (Process P107) in order to interrogate about the location area information of the receiving communication terminal 10. The gateway MSC 500 receives an SRIForSMack (SRIForSM Acknowledgement) signal (routing acknowledgement signal) from the HLR 30 (Process P108), determines the routing to an MSC in the area in which the receiving communication terminal 10 is located, and transfers the SM-MT signal to the MSC (Process P109). The gateway MSC 500 receives an SM-MT acknowledgement from the MSC to which it has sent the SM-MT signal (Process P110), the gateway MSC 500 transfers the SM-MT acknowledgement to the SMSC 40 (Process P111). Then, the SMS terminated control procedure ends. It should be noted that in the SMS terminated control procedure, the originating network does not make determination as to an SMS interconnection agreement.
Japanese Patent Laid-Open No. 2001-16632 discloses a technology that transfers a short message to a receiving terminal that subscribes to a carrier that does not have an SMS interconnection agreement. This technology also requires determination as to whether there is an SMS interconnection agreement between the carrier of the originating terminal and the carrier of the receiving terminal. Thus, accurate determination as to whether carriers have an SMS interconnection agreement with each other is crucial in a short-message originating and terminated control procedure.
In recent years, number portability systems have been introduced. Number portability is a system that enables communication terminal users to switch from one carrier to another while retaining their existing telephone number for sending and receiving messages.
If a receiving terminal has used number portability to switch to another carrier (hereinafter referred to as “using number portability”) and an originating terminal sends a short message to the receiving terminal, the following problem arises.
If the carrier of the originating terminal does not have an SMS interconnection agreement with the carrier to which a receiving terminal using number portability subscribes but has an SMS interconnection agreement with the carrier to which the receiving terminal subscribed before using number portability, a location-area MSC will erroneously determine in the SMS originating control procedure that the current carriers of the originating and receiving terminals have an SMS interconnection agreement with each other. However, a short message is not delivered to the receiving terminal but yet the originating terminal may be billed for the message. This erroneous determination is made because the telephone number of the receiving terminal is the same as the one used before using number portability and therefore the location-area MSC determines whether the carrier to which the receiving terminal subscribed before using number portability has a SMS interconnection agreement with the carrier of the originating terminal.
On the other hand, if the carrier of the originating terminal has an SMS interconnection agreement with the carrier to which a receiving terminal using number portability subscribes but does not have an SMS interconnection agreement with the carrier to which the receiving terminal subscribed before using number portability, the location-area MSC will determine erroneously in the SMS originating control procedure that the carriers do not have an SMS interconnection agreement with each other and therefore does not transfer a SM-MO signal to the short message center. Consequently, the originating terminal cannot send a short message to the receiving terminal. The same reason described above applies to this erroneous determination. As just described, there have been problems due to such erroneous determination, such as a short message not being sent to an intended receiving terminal or a short message not to be transferred to a receiving terminal being sent to a short message service center and the originating terminal is falsely billed for the message.